Energy
Energy
I. Metabolic PathwaysA. Energy = the ability to do work
B. Metabolic processes use chemical E (ATP)
C. E released when chemical bonds break (e- pulled apart)
D. Each step is regulated by
enzymes
II. EnzymesA. = proteins essential for
cells to function
B. Act as catalysts
1. Speed up reactions without being changed
2. Attach to substrate molecule and weaken it
3. Enzyme is not altered
C. Enzymes …. 1. Lower activation energy
(= energy that must be added to a reaction to cause molecules to react)
2. Form enzyme-substrate complexes
3. Allow reactions to proceed at certain temperatures and pH
D. Every enzyme catalyzes only one reaction or one type of reaction
E. Enzymes ….
1. break down toxins (a lot in liver)
2. speed up digestion
Catalase
III. Factors That Affect Enzyme SpeedA. Enzymatic reactions are rapid
1. Most occur 1000 times/secEx: 2H2O2 2H2O + O2
(600,000 times/sec with catalase). B. Temperature
1. Increase temp
Increase molecular collisions
Increase enzyme activity
2. Temp too high (or low?)….. breaks down (denatures) enzyme
3. Human enzymes function best at is 35o-40oC
Catalase
C. pH1. Each enzyme
has optimal pH
2. Large change in pH may denature the
enzyme3. Optimal in humans
pH 6-8D. Other factors: radiation,
electricity, chemicals.
I. Photosynthesis and NatureA. Sunlight provides energy to produce
carbohydrates.B. Equation:
Light
6CO2 + 6H2O C6H12O6 + 6O2
Chlorophyll
C. Autotrophs (make their own food)1. Algae, plants, some bacteria2. Ultimate source of food for life3. Photoautotrophs…..
use light energy4. Chemoautotrophs……
use chemical energyD. Photosynthesis produced the oxygen
in the atmosphere of our planet.
II. Structures of Photosynthesis
A. Chloroplasts
1. = the organelle of Photosynthesis
2. Stroma –
fluid-filled inner space
3. Thylakoids-
internal membranes within
stroma
4. Organized into stacks called grana.
B. Chlorophylls and other pigments are embedded within thylakoid membranes.
C. Pigments absorb solar energy.
III. Photosynthetic PigmentsA. Major pigments are
chlorophyll a and b.1. Both absorb violet, blue, and
red wavelengths best.2. Most green is reflected back.
B. Carotinoids = yellow-orange pigments ; absorb light in violet, blue, and green regions
C. In fall, chlorophyll breaks down and the yellow-orange pigments show through.
D. Accessory pigments capture light when sun changes positions.
IV. Cell RespirationA. Breaks down glucose and builds up ATP.
B. C6H12O6 + 6O2 6CO2 + 6H2O + ATP Energy
C. Begins in cytoplasm with Glycolysis
1. Turns glucose into pyruvic acid
2. Produces 2ATP
D. Fermentation
1. Processes that keep glycolysis going without oxygen
2. Lactic Acid fermentation
a) Converts pyruvic acid into lactic acid
b) Occurs in muscle cells when oxygen not available; causes pain
c) Used by bacteria that make yogurt, cheese, pickles
3. Alcoholic Fermentation
a) Converts pyruvic acid into ethyl alcohol and CO2
b) Occurs in bacteria and yeasts
c) Used to make beer, wine, and bread
E. Aerobic Respiration1. Need Oxygen2. Energy from Pyruvic Acid is
transferred to ATPa) In the Krebs Cycleb) In the Electron Transport
Chain3. Breakdown of glucose
yields 36 ATP
4. If O2 is not available to the cell, fermentation occurs.
Paper Chromatography